Artificial-slate blackboard



(No'ModeL) H. A. NEWMAN, J. D. WERDEN & 0. A. STEMPEL.

ARTIFICIAL SLATE BLAGKBOARD- Patented Jan. 31, 1893'.

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UNITED STATES Y HENRY A. NEWVMAN, OF HUNTSVILLE, JAMES D. WERDEN, OF KANSAS CITY,

PATENT OFFICE.

AND OMAR A. STEMPEL, OF ST. LOUIS, ASSIGNORS OF ONE-FOURTH TO- THOMAS M. ELMORE, OF HUNTSVILLE, MISSOURI.

ARTIFICIAL-SLATE BLACKBOARD.

SPECIFICATION forming part of Letters Patent No. 490,979, dated January 31, 1893.

Application filed February 6, 1892. Serial No. 420,520. (No specimens.)

To all whom it may concern.-

Be it known that we, HENRY A. NEWMAN, of Huntsville, Randolph county, JAMES D. WERDEN, of Kansas City, in the county of Jackson, and OMAR A. STEMPEL, of the city of St. Louis, State of Missouri, have invented a certain new and useful Improvement in Artificial-Slate Blackboards, of which the following is a full, clear, and exact descripro tion, reference being had to the accompanying drawings, forming part of this specification.

This invention relates to concrete, artificial slate black-boards, for use in school-rooms, lecture halls, &c., which concrete formation is reinforced bya sheet metal back, with flanged rims, the said sheet metal being perforated from the back, forming anchor like projections in front, and said flanged rims being perforated from the front, forming similar anchor like projections from said rims rearward, which forward and rearwardly projecting anchors securely hold the concrete of said artificial slate to said reinforce metal back,

2 5 and rim; and the invention further consists in features of novelty hereinafter fully described and pointed out in the claim.

Figure I is a front elevation of our artificial slate or concrete black-board and shows a de- 0 tail of the channel grooved molding that may securesaid black-board to the wall. Fig. II is a detail of the metal reinforce backing plate, with its flanged rim and anchor projections; and Fig. III is a vertical section 5 taken on line IIIIII, Fig. I and shows the artificial slate or concrete black-board, reinforced by the perforate metal back plate'and flanged rim, and the projecting anchors from the metal plate that secure the concrete 4o thereto.

Referring to the drawings:1 represents the metal reinforce backing plate, and 2 is the flange rim at the foot and top of said plate,

. which rim may, when required, be also con- 5 tinned around the ends of said metal backing plate. 3 represent perforations in said metal back, which perforations are punctured from the back forward; without cutting out the metal, so as to form forwardly projecting anchor clinches 4, that in conjunction with each other grasp and clutch the concrete. 5 represents like perforations from the front of said flange rim 2, which form like clutch anchors 6 to the anchors 4, except that said anchors 6 present backward, the reverse of the anchors 4, which present forward. 7 represents our artificial slate or concrete black-board compost, which after compounding is filled in said metal back reinforce frame, flush with the flange rims 2, and is composed of the following ingredientsz- Cement (preferably Portland), fine, sharp sand, lamp-black and ultra-marine.

The above-constituents are composted in preferably the following proportionsz-Oement, (preferably Portland) sixty-four pounds; fine, sharp sand thirty-two pounds; lamp black two pounds; ultra-marine, two pounds; makingin the aggregate one hundred pounds.

The respective amounts of cement and sand may be somewhat changed to accord with the grade and consequent price value of the artificial slates or cement black-boards-to be constructed. Also the amount of lamp-black and ultra-marine that enters into the compost,

may be varied in accordancewith the color required for said construction.

The color desired for said artificial slate or black-board, may largely depend on the color of the chalk or pencil to be used in marking thereon. For instance, if white chalk is used for the marker a dark slate or black board is desirable, and if on the other handred chalk is used for the marker, then a lighter color with a smaller quantity of lamp black, and a slates or cement black-boards are readily I overlaps it, and the composition molded on [0 seated. the plate Within the flanged rim; substan- In this application we claim the frame to tially as described.

which the composition is applied. HENRY A. NEWVMAN.

5' We claim as our invention:- JAMES D. WERDEN.

A black board consisting of a metal back- OMAR A. STEMPEL. ing plate 1 having a flanged rim 2, and punct- In presence ofures 3 and clinches 4 for holding the compo- BENJN. A. KNIGHT,

sition to the plate and to therim whose flange SAML. KNIGHT. 

